Workflow management via block chains

ABSTRACT

Techniques are disclosed for managing workflows using block chains. An entire workflow may be stored as a finite state machine on a block chain. Each data block of the block chain may correspond to a state and related operation of a workflow. Each data block of the block chain may be used as an input to a subsequent state of the workflow. Thus, any input may be used to compute the workflow even if the input is not designed to be used by a workflow. Nested block chains, each corresponding to a different workflow or different part of a workflow may be used to increase performance of computing the workflows.

BACKGROUND Field

Embodiments presented herein generally relate to techniques for managingworkflows using block chains. More specifically, embodiments presentedherein provide techniques for increasing the efficiency of processingworkflows based on attestations of successful completion of a previousworkflow operation.

Description of the Related Art

Workflow management is involves the administration of a set of states,conditions, or requirements to complete a task. A workflow may includeany activity that involves a set of steps to be completed in aparticular order. For example, a workflow may include a process to hirea new employee. In that case, a human resources (HR) group may completecertain forms, a facilities group may prepare an office for the newemployee, a group within the hiring company may be notified about thenew employee, etc.

Some workflows are simple while other workflows are complex. A simpleworkflow may involve deactivating a lock at a certain time of day. Amore complex workflow may involve assembling an airplane. Typicalworkflow management techniques involve a life-cycle of a particularprocess. Thus, a workflow may be improved until a new process iscreated. However, improving a complex workflow may not be possible dueto complexities of the workflow. For example, improvements to a workflowfor assembling an airplane may be limited by the number of pieces to beassembled. Further, determining a current state of the workflow may bedifficult due to the number of steps to assemble the airplane.

SUMMARY

One embodiment presented herein includes a computer implemented methodwhich generally includes obtaining a workflow specification and datarelated to the workflow specification, the workflow specificationcomprising one or more states and one or more operations, each operationcorresponding to at least one of the one or more states. The method mayalso include generating a block chain for the workflow specificationcomprising at least a first data block. The method may also includestoring the workflow specification and data related to the workflowspecification in the first data block. The method may also include, foreach of the one or more states, identifying an operation correspondingto a current state of the workflow, performing the operation, appendinga data block to the block chain, the appended data block including areference to the first data block and a reference to a data blockpreceding the appended data block and transitioning from the currentstate to a next state.

Another embodiment presented herein includes a computer-readable storagemedium storing instructions, which, when executed on a processor,perform an operation to manage workflows. The operation generallyincludes obtaining a workflow specification and data related to theworkflow specification, the workflow specification comprising one ormore states and one or more operations, each operation corresponding toat least one of the one or more states. The operation may also includegenerating a block chain for the workflow specification comprising atleast a first data block. The operation may also include storing theworkflow specification and data related to the workflow specification inthe first data block. The operation may also include, for each of theone or more states, identifying an operation corresponding to a currentstate of the workflow, performing the operation, appending a data blockto the block chain, the appended data block including a reference to thefirst data block and a reference to a data block preceding the appendeddata block and transitioning from the current state to a next state.

Still another embodiment presented herein includes system having aprocessor and a memory hosting an application, which, when executed onthe processor performs an operation to manage workflows. The operationgenerally includes obtaining a workflow specification and data relatedto the workflow specification, the workflow specification comprising oneor more states and one or more operations, each operation correspondingto at least one of the one or more states. The operation may alsoinclude generating a block chain for the workflow specificationcomprising at least a first data block. The operation may also includestoring the workflow specification and data related to the workflowspecification in the first data block. The operation may also include,for each of the one or more states, identifying an operationcorresponding to a current state of the workflow, performing theoperation, appending a data block to the block chain, the appended datablock including a reference to the first data block and a reference to adata block preceding the appended data block and transitioning from thecurrent state to a next state.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlyexemplary embodiments and are therefore not to be considered limiting ofits scope, may admit to other equally effective embodiments.

FIG. 1 illustrates an example computing environment, according to oneembodiment.

FIG. 2 illustrates an example workflow specification, according to oneembodiment.

FIG. 3 illustrates an example workflow and a corresponding block chain,according to one embodiment.

FIG. 4 illustrates a nested block chain, according to one embodiment.

FIG. 5 illustrates a method for generating a block chain for a workflow,according to one embodiment.

FIG. 6 illustrates an example computing system configured to generate ablock chain from a workflow, according to one embodiment.

DETAILED DESCRIPTION

Embodiments presented herein provide techniques for managing workflowsusing block chains. More specifically, embodiments presented hereinprovide techniques for generating a block chain for a workflow andmanaging state transitions of the workflow using data stored on theblock chain.

As discussed herein, a workflow processor obtains a workflowspecification and any data related to the workflow. The workflowspecification may include the finite number of states of the workflow,an operation performed in each state to transition to a subsequentstate, and a subsequent state for each of the finite number of states.The workflow specification may be represented a finite state machine.That is, the workflow and a corresponding block chain may be in one of afinite number of states at a given time. An input for a given operationof the workflow may include an attestation that a previous state oroperation has occurred. Thus, any input may be used to perform theworkflow even if the input is not designed for a workflow.

An output from a given state of the workflow may be determined based onboth a current state of the workflow and one or more current inputs tothe workflow. For example, the workflow may be represented by a Mealymachine. In general, a Mealy machine is a finite state machine with anoutput from a give state determined based on both a current state and acurrent input.

Data related to the workflow may include data needed to initiate theworkflow. The data related to the workflow may be different for eachworkflow. For example, a given workflow may correspond to steps toassemble an airplane. The data related to the workflow may identify eachpiece of the plane to be assembled. The pieces of an airplane to beassembled may be different that data related to a workflow for signing adocument.

The obtained workflow specification may be one of many workflowspecifications managed by a block chain. Generally, a block chain is adata structure that records data. Each update to the data in the blockchain may be stored in a new block or link in the block chain. Each newblock may be cryptographically bound to a previous data block in theblock chain. Once data is appended to the block chain, that data cannotbe modified without damaging one or more links in the block chain. Thus,validity of the data in the block chain may be analyzed by checking thecryptographic bindings between the data blocks. Any modification of thedata in the block chain may be readily detected and can be remedied.

Once the workflow is obtained, the workflow processor may executeoperations of the workflow. Each operation of the workflow maycorrespond to a state of the workflow and block chain. At each state(i.e., step) of the workflow an input may be received which indicatesthat an operation corresponding to a previous state has been completed.Thus, once an operation is performed in a given state, the workflowprocessor may provide an attestation that the given state occurred.

Upon the completion of each operation and corresponding state of theworkflow, a data updater may append a new data block to the block chain.The new data block may indicate that the operation has been completed.For example, a given operation may involve installing a wing on theairplane. Once the wing is installed, the data updater may append a newdata block to the block chain. The new data block may indicate that thewing has been installed.

An appended data block may include a reference to a first data block ofthe block chain. The reference to the first data block may identify anorigin of the block chain. The appended data block may also refer to aninput on which the appended data block depends. The input may include adata block related to the workflow being processed and immediatelypreceding the appended data block on the block chain.

Upon completion of a given workflow, a final state of that workflow mayindicate that the workflow is completed. For example, when the lastpiece of the airplane is installed, the final state of the workflow maybe “complete.” Once the block chain is appended to indicate that theworkflow is completed, all states and corresponding operations of theworkflow are represented on the block chain.

Advantageously, storing a workflow as a finite state machine and using ablock chain allows an observer to verify a current state of a givenworkflow. In this context, an observer may be the workflow processor, aworkflow designer, an application executing on a client device or on aserver computer, or the like. In one embodiment, the observer may havepermission to view one or more states of the workflow and block chain.

Using a block chain also allows the occurrence of a given state of theworkflow to be verified externally. That is, each data block in a blockchain provides an attestation that a corresponding state of the workflowoccurred and that the operation of that state has been satisfied. Theattestation that a state occurred may be verified based on acryptographic link between the data blocks of the block chain. A datablock may be appended to the block chain for a completed state of theworkflow. The appended data block may be linked to a previous data blockin the block chain. Thus, the presence of a data block on the blockchain corresponding to a state of the workflow may indicate that thestate occurred.

The block chain may also allow detection of a modification to any datain the block chain. For example, when data in the block chain ismodified, a hash of that data block may be changes. Thus, a link betweenthat data block and a subsequent data block in the block chain may bebroken. The broken link in the block chain may be identified byverifying each link in the block chain.

Each data block of the block chain may be used as an input to asubsequent state of the workflow. Thus, any input may be used to performthe workflow even if the input is not specifically designed to be usedby a workflow. For example, a clock application executing on a computingdevice may be designed to maintain a current time. However, the outputof the clock application (e.g., the current time) may not be compatiblewith the workflow (e.g., an incompatible data type). In that case, thecurrent time may be stored in a data block of the block chain. Thus, thecurrent time on the data block can be used as an input to a givenoperation of the workflow.

An additional advantage provided by storing a workflow as a finite statemachine on a block chain is that a given data block in a first blockchain may include a reference to a data block in one or more other blockchains. That is, a state of the workflow corresponding to the firstblock chain may depend on an occurrence of a state of a differentworkflow.

A given operation in a workflow may depend on a successful completion ofa separate workflow. That is, a given data block in a main block chainmay include a reference to an identifier of the separate block chain.Rather than referencing a separate block chain, the given data block inthe main block chain may include the separate block chain as a state ofthe corresponding workflow. The separate block chain stored in the givendata block may be secured with a shared secret. That is, the separateblock chain may be encrypted using the shared secret.

The shared secret may be known by certain parties associated with theseparate block chain and a corresponding workflow. The certain partiesmay have permission to observe one or more states of a workflowcorresponding to the separate block chain. However, a third partyobserver with permission to view the main block chain may not have theshared secret. Thus, the third party observer may be able to view andverify the states of the main block chain, but could not view the statesof the separate block chain. In that case, the given data block storingthe separate block chain may appear to the observer as a single statethat occurred.

The data block storing the separate block chain and the data blockincluding a reference and depending from another block chain or a datablock in a separate block chain may be examples of a nested block chain.That is, one or more block chains and corresponding workflows may benested within a larger block chain and workflow. A nested block chainmay increase performance of computing a workflow by decreasing the sizeof a given workflow into separate and smaller workflows. That is,processing speed of the given workflow may be increased over a single,large workflow.

The nested block chain may also provide increased security as to thedetails of the corresponding workflow. That is, a block chaincorresponding to a smaller nested workflow may be encrypted using ashared secret. The shared secret may be known to parties associated withthe workflow, but unknown to third parties. Thus, an observer (e.g., athird party) cannot inspect details of the workflow or correspondingblock chain without the shared secret.

FIG. 1 illustrates an example computing environment 100, according toone embodiment. As shown, the computing environment includes a network105, one or more clients 110 a server computer 120, and a datarepository 130. The network 105 may be representative of a cellularnetwork, local area network, or similar network. As illustrated, theserver computer 120 includes a workflow processor 122, a data updater124, and a state based machine 126.

The clients 110 may be representative of a computing platform such as adesktop computer, a laptop computer, a tablet, or a mobile device. Aclient 110 may be used to generate a workflow. A client 110 may also beused to observe a block chain associated with a workflow to determine acurrent state of the workflow or verify that a given state has occurred.

The data repository 130 may be representative of a database or otherdata storage mechanism. The data repository 130 may store one or moreworkflows and corresponding block chains. Each block chain may be a datastructure to record data related to a corresponding workflow. Data inthe block chain may be updated by appending a new block or link to theblock chain. The new data block may be cryptographically bound to aprevious data block in the block chain. That is, a given link in theblock chain may contain a cryptographic hash of the block chain from thefirst data block to the data block immediately preceding the link. Thus,the given link may contain a history of the block chain preceding thatlink. Once a block chain is created, modification to data in the blockchain may damage one or more links or bindings between data blocks inthe block chain. Thus, the validity and security of a given block chainmay be confirmed based on the cryptographic bindings between the blocks.A modification to the data in the block chain is readily detected byidentifying a break in the block chain. For example, modification ofdata in a given data block may break a link to a subsequent data blockthat depend on the modified data block.

The workflow processor 122 may obtain a workflow specification from thedata repository 130. The workflow processor 122 may locate the workflowspecification based on a workflow to be processed to perform a giventask. The workflow specification may also be referenced by anotherworkflow being processed by the workflow processor 122. The workflowspecification may include each state of the workflow and an operationperformed during each state to transition to a next state of theworkflow. The workflow specification is described in more detail belowwith reference to FIG. 2.

The workflow processor 122 may also obtain any data related to theworkflow specification from the data repository 130. A location of datarelated to the workflow specification may be determined based on amapping. The mapping may indicate a location in the data repository 130of data related to each workflow specification. For example, datarelated to a workflow for an invoice to a transaction may include anidentity of a buyer, an identity of a seller, an item transferredbetween the buyer and seller, a price of the item transferred, etc. Therelated data may be an input to a first state of the workflow.

Upon obtaining a workflow specification and related data, the workflowprocessor 122 may create a block chain for the workflow. To do so, theworkflow processor 122 may combine the workflow specification and anyrelated data into a data block. To combine the workflow specificationand related data, the workflow processor 122 may append the related datato the workflow specification. The workflow processor may also identifythe workflow specification and the related data as a linked pair. Thecombined data block may be stored in a first data block of the blockchain. The first data block may be referred to as commit zero (C0). Theworkflow processor 122 may compute a hash of C0. The hash may be used asa universally unique identifier (UUID) of the block chain.

Each data block in the block chain following C0 may refer to C0 (e.g.,the UUID of C0) as the origin of the block chain and a correspondingworkflow. The reference to C0 allows an observer to identify a currentstate of a particular workflow. For example, a given block chain mayinclude data from more than one workflows. That is, the block chain mayinclude data blocks corresponding to each state of more than oneworkflow. To identify a current state of a particular workflow, anobserver can look at a most recent data block of a corresponding blockchain and identify the workflow from the reference to the first datablock of that block chain. Thus, the observer need not re-trace eachstate of the workflow in reverse to determine an identity of theworkflow or block chain.

The creation of the block chain may satisfy a first state of theworkflow. In that case, the data updater 124 may update the block chainto indicate that C0 an operation corresponding to C0 is completed. Thestate based machine 126 may transition from the first state of theworkflow to a second state. The data updater 124 may append a new datablock to the block chain. The new data block may be referred to ascommit one (C1).

The workflow processor 122 may perform an operation corresponding to C1and the second state of the workflow. An input to a given operation mayinclude an attestation to a previous block in the block chain. The inputof the given operation may also include an output from an operationcorresponding to a previous state of the workflow. For example, theoperation corresponding to C1 may include an attestation to C0. Theattestation may indicate that C0 successfully completed (i.e., the blockchain was created). Once the workflow processor 122 completes theoperation corresponding to C1 (or satisfies a condition of C1), the dataupdater 124 may update the block chain to indicate that the operationcorresponding to C1 completed successfully. The state based machine 126may transition to the next state of the workflow specification and thedata updater 124 may append a new data block (for commit 2 (C2)) to theblock chain.

In one embodiment, the input may include a separate block chainreferenced by the given operation. That is, the given operation mayrefer to a block chain separate from the block chain containing thegiven operation. The separate block chain may correspond to a separateworkflow specification and a separate set of inputs.

The workflow processor 122 may continue to perform operationscorresponding to each state of the workflow until the workflow iscompleted and a current state identifies the workflow as “complete.” Thedata updater 124 may also continue to append a data block to the blockchain for each state that is satisfied. Further, the state based machine126 may transition through each state of the workflow. Once a data blockappended to the block chain indicates that the workflow is complete, thecompleted block chain may be stored in the data repository 130.

In one embodiment, a workflow software agent (not shown) executing on aclient 110 may be used to generate a workflow and implement the workflowas an application on the client 110. The workflow software agent maygenerate an initial representation of a workflow state and store thatrepresentation on the block chain. Other software agents, eachrepresenting an attestation to the occurrence of a state of the workflowmay communicate with the workflow software agent to update and verify acurrent state of the workflow. Upon each update to the current state ofthe workflow, the workflow software agent may append a data block to thehash chain representing the current state of the workflow.

FIG. 2 illustrates an example workflow specification 200, according toone embodiment. As shown, the workflow specification 200 includescurrent states 205, operations 210, and new states 215. A workflowprocessor may obtain a workflow specification to process a workflow. Theworkflow specification 200 may provide steps to be performed to executethe workflow. The workflow may be executed by performing each step on astate based machine. Each step of the workflow may correspond to anoperation 210 to be performed in a current state 205 of the workflow.

At any given time, the state based machine may be in one of the currentstates 205. To transition out of a current state 205 to another state215 in the workflow specification 200, the workflow processor performs acorresponding operation. For example, to transition out of the “start”state, the operation of “SimpleInvoice.accept(signature=Ysignature)” isexecuted. In one embodiment, only one operation allows the state basedmachine to transition from a given current state to a corresponding newstate. That is, the state based machine may not transition out of thecurrent state until the workflow processor successfully performs acorresponding operation.

Returning to the invoice example discussed above, upon obtaining theworkflow specification, the state based machine is in an initializedstate as shown by the current state of “init.” The workflow processormay execute the corresponding operation to create a workflow for theinvoice. Once the workflow is created, a data updater may update a blockchain for the workflow to indicate that the creation operation completedsuccessfully. The state based machine may also transition to the “start”state.

The workflow processor may execute an operation for a buyer (Y) toaccept an offer made by a seller (X). This operation is illustrated asthe operation “SimpleInvoice.accept(signature=Ysignature)” as shown inFIG. 2. Execution of this operation may involve the workflow processoraccepting the offer on behalf of the buyer (Y). Executing the operationmay also involve waiting until the workflow processor receivesacceptance from the buyer (Y). That is, the execution of the operationmay pertain to an active or a passive execution.

Once the operation for the buyer (Y) to accept the offer is successfullycompleted, the data updater may append a data block to the block chain.The appended data block may be referred to as commit one (C1). The statebased machine may transition from the “start” state to the “accepted”state.

While the state based machine is in the “accepted” state, the workflowprocessor may execute an operation to ship one or more items (e.g.,goods) from the seller (X) to the buyer (Y). As discussed above, thestate based machine may not transition from the “accepted” state to a“shipped” state until the one or more items have been shipped. Theworkflow processor may execute the operation to ship the one or moreitems or may wait to receive a confirmation that the one or more itemshave been shipped.

When the one or more items have shipped, the data updater may append adata block to the block chain. The appended data block may be referredto as commit two (C2) and indicate that the one or more items have beensuccessfully shipped to the buyer (Y). The state based machine maytransition to the “shipped” state once the operation corresponding tothe “accepted” state is completed.

The workflow processor may continue to execute an operation in each ofthe remaining states (e.g., received, pay, paid, and complete) until thestate based machine is in the “complete” state. The data updater mayappend a data block to the block chain for each state. The appended datablocks may indicate that the operation corresponding to each state hasoccurred. Once the state based machine transitions to a state thatindicates the workflow is complete, the block chain may be stored in adata repository. A mapping may also be updated to associate the blockchain with the corresponding workflow specification.

FIG. 3 illustrates an example workflow 300 and a corresponding blockchain 305, according to one embodiment. As discussed above, a workflowprocessor may obtain a workflow specification and data related to theworkflow. The workflow specification may provide one or more states of astate based machine. To transition from a given state in the workflowspecification (i.e., a step in the workflow 300) to a next state, theworkflow specification may provide an operation to be satisfied. In oneembodiment, the state based machine transitions to the next state uponthe successful execution or completion of the operation corresponding tothe current state of the state based machine.

The workflow illustrated in FIG. 3 may correspond to a given workflowspecification obtained by the workflow processor. Once obtained, theworkflow processor may create a block chain. A first data block of theblock chain may indicate that the block chain has been created. Thesingle data block may correspond to commit zero (C0) as shown in theblock chain 305. A hash of C0 may be used as a UUID for the block chain305. As each step in the workflow 300 is completed, a data block may beappended to the block chain 305 as shown by C1-C6. Each data block ofthe block chain 305 may include a reference to the first data block inthe clock chain (C0). This reference may be used to identify the blockchain 305 associated with each of the data blocks.

As illustrated, workflow 300 may be associated with an invoice for atransaction between a seller (X) and a buyer (Y). The workflow 300 maycorrespond to the workflow specification as described with reference toFIG. 2. Once the block chain is created, the workflow 300 begins at astart state 310. That is, the start state 310 is the current state ofthe state based machine. To transition the state based machine from thestart state 310 to the accepted state 315, the workflow specificationmay provide that an operation be satisfied.

To satisfy the operation of the start state 310, the buyer (Y) mayaccept an offer from the seller (X) to purchase an item(s). Uponacceptance of the buyer (Y), the state based machine may transition tothe accepted state 315. A data updater may append a new data block tothe block chain 305 which indicates that the buyer (Y) accepted theoffer. The new data block may be represented by C1 in the block chain305. The new data block (C1) may include a first and a second referenceto the C0 data block. The first reference to C0 may identify an originof the current workflow. The second reference to C0 may identify acommit or data block upon which the new data block depends.

An operation to be satisfied in the accepted state 315 may require theseller (X) to ship the item(s) purchased by the buyer (Y). Once theitem(s) is shipped, the state based machine transitions to the shippedstate 320. The data updater appends a data block (C2) to the block chain305. The C2 data block indicates that the seller (X) has shipped theitem(s) related to the invoice. The C2 data block may refer to the C0data block as the origin of the workflow and the C1 data block as thedata block from which C2 depends, as shown in block chain 305.

The state based machine may remain in the shipped state 320 until anoperation corresponding to that state is satisfied. The operation of theshipped state may be satisfied when the buyer (Y) receives the item(s)purchased from and shipped by the seller (X). In addition to receivingthe item(s), the operation may be satisfied upon the buyer (Y) acceptingor approving the shipment of the item(s). Upon receipt of the item(s),the state based machine transitions from the shipped state 320 to thereceived state 325. The data updater appends a data block to the blockchain 305. The appended data block may refer to C3 as shown in the blockchain 305. As shown, the C3 data block refers to the C0 data block asthe origin of the workflow and C2 as the data block from which C3depends.

An operation in the received state 325 may be satisfied when the seller(X) invoices the buyer (Y) for the item(s). Upon invoicing for thereceived item(s), the state based machine transitions to the pay state330. Accordingly, the data updater appends a data block (C4) to theblock chain 305. As shown, the C4 data block refers to C0 as the originof the block chain 305. The C4 data block also refers to C3 as the datablock from which C4 depends.

An operation of the pay state 330 may be satisfied upon the payment forthe item(s). Once payment for the item(s) is complete, the state basedmachine transitions to the paid state 335. The data updater appends theblock chain to include a data block (C5) which indicates that theinvoice has been paid. The C5 data block refers to the C0 block as theorigin of the workflow and the C4 data block from which C5 depends.

When the seller (X) receives payment for the item(s), the state basedmachine transitions to the complete state 340. Accordingly, the dataupdater appends a data block (C6) to the block chain 305. The appendeddata block C6 may indicate that the workflow for the invoice iscomplete. As shown, the C6 data block may refer to C0 as the origin ofthe workflow and the C5 data block from which the C6 data block depends.Once the current state of the state based machine is the complete state340, the block chain for the workflow is complete and may be stored in adata repository.

FIG. 4 illustrates a nested block chain 400, according to oneembodiment. As shown, the nested block chain includes three separateblock chains 405, 410 and 415. Each of the separate block chains 405,410 and 415 each contain data blocks 420, 422, 424, 426, and 428. Eachdata block of a block chain (e.g., 420, 424, and 428) may include anattestation that an operation for a corresponding state of an associatedworkflow was successful. Thus, each data block of a given block chainmay correspond to at least one state of a workflow.

A workflow processor may compute a unique identifier (UUID) for eachblock chain. To do so, the workflow processor may compute a hash of afirst data block in the block chain. Each data block in a given blockchain may include a reference to a first data block of that block chain.That is, each data block in the given block chain may reference the UUIDfor that block chain. For example, each data block in block chain 405may include a reference to UUID-1. Similarly, each data block in blockchain 410 may include a reference to UUID-2, and each data block inblock chain 415 may include a reference to UUID-3.

The reference in each data block to the UUID of the block chain mayallow an observer to identify a current state of a given workflow orstate based machine based on a most recent update to the block chain.For example, a data reference to the UUID of the block chain may allowan observer to easily determine a block chain and workflow correspondingto the UUID. Once the UUID of a block chain is identified, the observermay determine a corresponding workflow from a mapping.

A given data block in a block chain may refer to a UUID of a separateblock chain. That is, a given operation of a workflow may be dependenton an operation of another workflow. For example, as shown, data block422 of block chain 405 refers to a UUID of block chain 410 (e.g.,UUID-2). Thus, a state of a workflow corresponding to block chain 405may depend on an operation of or an output from a workflow correspondingto block chain 410. The operation corresponding to data block 422 mayspecify that a particular output be received from the block chain withUUID-2 (i.e., block chain 410). The particular output may involve anattestation that block chain 410 completed successfully, a particulartype of output, a particular value, etc.

As operations of the workflow corresponding to block chain 410 areprocessed, a corresponding data block is appended to the block chain410. An operation corresponding to data block 426 may include areference to block chain 415. That is, the operation corresponding todata block 426 may not refer to a prior operation in the workflow.Rather, the operation of data block 426 may refer to a UUID of blockchain 415 (e.g., UUID-3). In that case, the data block 426 may refer toblock chain 415 rather than a preceding data block in block chain 410.Thus, an operation of the workflow corresponding to data block 426 maydepend on an output of block chain 415.

FIG. 5 illustrates a method 500 for generating a block chain for aworkflow, according to one embodiment. As shown, the method 500 beginsat step 505, where a workflow processor receives an input. If a blockchain has not been created for the workflow, the input may include aworkflow specification and data related to that workflow. If a blockchain has been created for the workflow, the input may include anattestation that an operation of the workflow step corresponding to theprevious data block successfully completed.

At step 510, the workflow processor determines whether the inputreferences a previous data block in the block chain. If the inputincludes the workflow specification and related data, the input may notreference a previous block in the block chain. In that case, theworkflow processor combines the input of a workflow specification anddata related to that workflow. The workflow processor may determine ahash of the combined data using a cryptographic hash function at step520. The hash may be used as a UUID of the block chain.

If the input at step 510 includes an attestation that a previousoperation of the workflow corresponding to the previous data blocksuccessfully completed, the input refers to a previous data block in theblock chain. At step 515, the workflow processor authenticates the blockchain. To do so, the workflow processor may verify the links betweeneach block of the block chain. A link in the block chain may include ahash of the block chain preceding the link. That is, a given link mayinclude a hash of the block chain from the first data block to the datablock immediately preceding that link.

Thus, to verify a link in the block chain, the workflow processor maydetermine a hash of the block chain from the first data block to thedata block preceding the link. The workflow processor may compare thedetermined hash to the hash stored in the link. A difference between thehashes may indicate that at data in at least one data block precedingthe link has been modified. Verifying a given link in the block chainensures that no data has been modified in one or more data blockspreceding that link.

At step 525, the workflow processor determines whether theauthentication of the block chain, completed at step 515, wassuccessful. Upon determining the authentication was successful, theworkflow processor creates a data block in the block chain at step 530.The created data block may correspond to an operation in the workflowbeing analyzed.

If the input to step 530 is a hash from step 520 of the workflowspecification and related data, the data block created at step 530 maybe the first data block in the block chain. Thus, creation of the datablock may also create the block chain for the workflow. The created datablock may include an attestation that the corresponding operation wascompleted successfully. The data block may also include a reference tothe first data block in the block chain as well as a data blockimmediately preceding the created data block in the block chain. A dataupdater may append the created data block to the block chain.

If the workflow processor determines, at step 525, that theauthentication of the block chain at step 515 failed, the workflowprocessor terminates the workflow at step 535. At step 540, the workflowprocessor determines whether the created data block corresponds to thelast step in the workflow. If not, the workflow processor receives aninput at step 505. The steps of method 500 continue to repeat until anauthentication of the block chain fails or a data block appended to theblock chain corresponds to the last step in the workflow.

FIG. 6 illustrates an example computing system 600 configured togenerate a block chain from a workflow, according to one embodiment. Asshown, the computing system 600 includes, without limitation, a centralprocessing unit (CPU) 605, a network interface 615, a memory 620, andstorage 630, each connected to a bus 617. The computing system 600 mayalso include an I/O device interface 610 connecting I/O devices 612(e.g., keyboard, display, mouse devices, image capture devices, etc.) tothe computing system 600. Further, the computing elements shown incomputing system 600 may correspond to a physical computing system(e.g., a system in a data center) or may be a virtual computing instanceexecuting within a computing cloud.

The CPU 605 retrieves and executes programming instructions stored inthe memory 620 as well as stored in the storage 630. The bus 617 is usedto transmit programming instructions and application data between theCPU 605, I/O device interface 610, storage 630, network interface 615,and memory 620. Note, CPU 605 is included to be representative of asingle CPU, multiple CPUs, a single CPU having multiple processingcores, and the like, and the memory 620 is generally included to berepresentative of a random access memory. The storage 630 may be a diskdrive or flash storage device. Although shown as a single unit, thestorage 630 may be a combination of fixed and/or removable storagedevices, such as fixed disc drives, removable memory cards, opticalstorage, network attached storage (NAS), or a storage area-network(SAN).

As shown, storage 630 includes workflow specifications 632, workflowdata 634, and block chains 636. The workflow data 634 may include datarelated to each workflow specification in the workflow specifications632. The block chains 636 may include a block chain for each workflowspecification in the workflow specifications 632. The storage 630 mayalso include a mapping 638. The mapping may provide a link between eachof the workflow specifications 632, the workflow data 634, and the blockchains 636. The mapping may be used to determine a location a givenworkflow specification, related workflow data, and a corresponding blockchain.

Illustratively, the memory 620 includes a workflow processor 622, a dataupdater 624, and a state based machine 626. In certain aspects, thesecomponents may correspond to the components of the server computerdescribed with reference to FIGS. 1-3. For example, the workflowprocessor 622 may obtain a workflow specification and data related tothe workflow specification from workflow specifications 632 and workflowdata 634, respectively.

Each workflow specification in workflow specifications 632 may includeone or more states and corresponding operations for a given workflow.The workflow data 634 may include data related to each workflowspecification in workflow specifications 632. As an example, a givenworkflow specification may relate to an invoice for a transactionbetween two or more parties. In that case, the data related to the givenworkflow may include an identity of the parties involved, an item(s)related to the transaction, a price of the item(s), etc.

Upon obtaining the workflow specification and related data, the workflowprocessor 622 may create a block chain for the workflow specification.The workflow processor 622 may combine the workflow specification andrelated data. The workflow processor 622 may store the combined data ina first data block of the block chain. In the block chain, the firstdata block may be referred to as commit zero (C0). The workflowprocessor 622 may determine a hash of the combined data which may beused as a UUID of the block chain.

Each data block in a given block chain may refer to the UUID of thatblock chain. The reference to the UUID of the block chain associates thedata block to the block chain. Thus, an observer can easily identify ablock chain associated with a given data block. Identifying a blockchain associated with a given data block may be useful when a blockchain includes data blocks associated with more than one workflow. Eachdata block may also refer to an input on which the data block depends.The referenced input may be a data block immediately preceding the givenblock in the block chain or a data block in a separate block chain. Theinput may also be a service that is not related to a workflow. Forexample, a given data block may refer to an external service thatprovides a time stamp. If there is a nested block chain, each blockchain may refer to a single service to provide a particular piece ofdata.

Once the block chain is created, the state based machine 626 maytransition to a start state of the workflow. The data updater 624 mayappend a new data block to the block chain. The new data block may bereferred to as commit one (C1). The C1 data block may correspond to afirst state of the workflow. The C1 data block may include a referenceto the C0 data block.

The workflow processor 622 may perform an operation corresponding to thefirst state of the workflow. An input to the operation may include anattestation that the block chain has been created and hash of theworkflow specification and related data has been computed. Uponcompletion of the operation corresponding to the first state of theworkflow, the workflow processor 622 may identify a next state of theworkflow. The state based machine 626 may transition to the next stateof the workflow and the data updater 624 may append a new data block tothe block chain.

The appended data block may be referred to as commit two (C2). The C2data block may include a reference to the UUID of the block chain (e.g.,a hash of the C0 data block). The C2 data block may also include areference to an input on which the C2 block depends. The input mayinclude a data block on the block chain related to the workflow beingprocessed and immediately preceding the C2 data block (i.e., the C1 datablock). The input may also include a data block in a separate blockchain. The input may also include a separate block chain or a serviceexternal to the workflow. For example, the input may include a timestamp from a service designed to provide a current time.

In one embodiment, an input for a data block on a main block chain mayinclude a separate block chain. In that case, an operation correspondingto a state of the main block chain may specify that a workflowassociated with the separate block chain be executed before the statebased machine 626 can transition to a next state of the main blockchain. The workflow processor 622 may process the separate block chainand associated workflow in a manner similar to that described above.

For example, the workflow processor 622 may obtain a workflowspecification associated with the separate block chain. The workflowprocessor 622 may perform an operation for each state of the separateblock chain. Upon successful completion of each state of the separateblock chain, the state based machine 626 may transition from a currentstate of the separate block chain to a next state of the separate blockchain. Similarly, the data updater 624 may append a new data block tothe separate block chain for each completed state of the separate blockchain. The data blocks appended to the separate block chain each mayindicate that a corresponding state occurred.

Upon completion of the workflow associated with the separate blockchain, the data updater 624 may append a new data block to the mainblock chain. The appended data block may indicate that the workflowassociated with the separate block chain was successfully completed. Theworkflow processor 622 may continue to complete an operation for eachstate of the workflow until each state of the workflow has occurred. Afinal state of the workflow may indicate that the workflow is completed.Upon completion of the workflow, the workflow processor 622 may storethe completed block chain in block chains 636.

It may be noted that, descriptions of embodiments of the presentdisclosure are presented above for purposes of illustration, butembodiments of the present disclosure are not intended to be limited toany of the disclosed embodiments. Many modifications and variations willbe apparent to those of ordinary skill in the art without departing fromthe scope and spirit of the described embodiments. The terminology usedherein was chosen to best explain the principles of the embodiments, thepractical application or technical improvement over technologies foundin the marketplace, or to enable others of ordinary skill in the art tounderstand the embodiments disclosed herein.

In the preceding, reference is made to embodiments presented in thisdisclosure. However, the scope of the present disclosure is not limitedto specific described embodiments. Instead, any combination of thefollowing features and elements, whether related to differentembodiments or not, is contemplated to implement and practicecontemplated embodiments. Furthermore, although embodiments disclosedherein may achieve advantages over other possible solutions or over theprior art, whether or not a particular advantage is achieved by a givenembodiment is not limiting of the scope of the present disclosure. Thus,the following aspects, features, embodiments, and advantages are merelyillustrative and are not considered elements or limitations of theappended claims except where explicitly recited in a claim(s). Likewise,reference to “the invention” shall not be construed as a generalizationof any inventive subject matter disclosed herein and shall not beconsidered an element or limitation of the appended claims except whereexplicitly recited in a claim(s).

Aspects of the present disclosure may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “component,” “circuit,” “module” or “system.”Furthermore, aspects of the present disclosure may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples a computer readable storage medium include: anelectrical connection having one or more wires, a hard disk, a randomaccess memory (RAM), a read-only memory (ROM), an erasable programmableread-only memory (EPROM or Flash memory), an optical fiber, a portablecompact disc read-only memory (CD-ROM), an optical storage device, amagnetic storage device, or any suitable combination of the foregoing.In the current context, a computer readable storage medium may be anytangible medium that can contain, or store a program.

The flowcharts and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. Each block of the block diagrams and/orflowchart illustrations, and combinations of blocks in the blockdiagrams and/or flowchart illustrations can be implemented byspecial-purpose hardware-based systems that perform the specifiedfunctions or acts, or combinations of special purpose hardware andcomputer instructions.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A computer-implemented method for managingworkflows comprising: obtaining a workflow specification and datarelated to the workflow specification, the workflow specificationcomprising one or more states and one or more operations, each operationcorresponding to at least one of the one or more states; generating ablock chain for the workflow specification comprising at least a firstdata block; storing the workflow specification and data related to theworkflow specification in the first data block; and for each of the oneor more states: identifying an operation corresponding to a currentstate of the workflow; performing the operation; appending a data blockto the block chain, the appended data block including a reference to thefirst data block and a reference to a data block preceding the appendeddata block; and transitioning from the current state to a next state. 2.The method of claim 1, wherein the data block appended to the blockchain includes a reference to another block chain.
 3. The method ofclaim 1, further comprising: obtaining a workflow specificationassociated with the other block chain, the workflow specificationassociated with the other block chain containing one or more operationsfor the workflow specification associated with the other block chain;and performing an operation corresponding to each of the one or moreoperations for the workflow specification associated with the otherblock chain.
 4. The method of claim 3, wherein the appended data blockincludes each of the one or more operations for the workflowspecification associated with the other block chain.
 5. The method ofclaim 1, wherein a cryptographic hash creates a link between each datablock and a preceding data block and creates a link between each datablock and a subsequent data block.
 6. The method of claim 5, furthercomprising: authenticating the block chain by verifying the linksbetween each of the data blocks in the block chain.
 7. The method ofclaim 1, wherein an input to each of the one or more operations includesat least an attestation to an occurrence of a state corresponding to apreceding operation.
 8. The method of claim 1, further comprising:computing a hash of the workflow specification and data related to theworkflow specification; and assigning the hash as an identifier of theblock chain.
 9. A computer-readable storage medium storing instructions,which, when executed on a processor, perform an operation to manageworkflows, the operation comprising: obtaining a workflow specificationand data related to the workflow specification, the workflowspecification comprising one or more states and one or more operations,each operation corresponding to at least one of the one or more states;generating a block chain for the workflow specification comprising atleast a first data block; storing the workflow specification and datarelated to the workflow specification in the first data block; and foreach of the one or more states: identifying an operation correspondingto a current state of the workflow; performing the operation; appendinga data block to the block chain, the appended data block including areference to the first data block and a reference to a data blockpreceding the appended data block; and transitioning from the currentstate to a next state.
 10. The computer-readable storage medium of claim9, wherein the data block appended to the block chain includes areference to another block chain.
 11. The computer-readable storagemedium of claim 9, the operation further comprising: obtaining aworkflow specification associated with the other block chain, theworkflow specification associated with the other block chain containingone or more operations for the workflow specification associated withthe other block chain; and performing an operation corresponding to eachof the one or more operations for the workflow specification associatedwith the other block chain.
 12. The computer-readable storage medium ofclaim 11, wherein the appended data block includes each of the one ormore operations for the workflow specification associated with the otherblock chain.
 13. The computer-readable storage medium of claim 9,wherein a cryptographic hash creates a link between a data block and apreceding data block and creates a link between the data block and asubsequent data block.
 14. The computer-readable storage medium of claim9, the operation further comprising: authenticating the block chain byverifying the links between each of the data blocks.
 15. A system,comprising: a processor; and a memory hosting an application, which,when executed on the processor, performs an operation to manageworkflows, the operation comprising: obtaining a workflow specificationand data related to the workflow specification, the workflowspecification comprising one or more states and one or more operations,each operation corresponding to at least one of the one or more states;generating a block chain for the workflow specification comprising atleast a first data block; storing the workflow specification and datarelated to the workflow specification in the first data block; and foreach of the one or more states: identifying an operation correspondingto a current state of the workflow; performing the operation; appendinga data block to the block chain, the appended data block including areference to the first data block and a reference to a data blockpreceding the appended data block; and transitioning from the currentstate to a next state.
 16. The system of claim 15, wherein the datablock appended to the block chain includes a reference to another blockchain.
 17. The system of claim 15, the operation further comprising:obtaining a workflow specification associated with the other blockchain, the workflow specification associated with the other block chaincontaining one or more operations for the workflow specificationassociated with the other block chain; and performing an operationcorresponding to each of the one or more operations for the workflowspecification associated with the other block chain.
 18. The system ofclaim 17, wherein the appended data block includes each of the one ormore operations for the workflow specification associated with the otherblock chain.
 19. The system of claim 15, wherein a cryptographic hashcreates a link between a data block and a preceding data block andcreates a link between the data block and a subsequent data block. 20.The system of claim 15, the operation further comprising: authenticatingthe block chain by verifying the links between each of the data blocks.